Predictors of successful weight loss with relative maintenance of fat-free mass in individuals with overweight and obesity on an 8-week low-energy diet

A low-energy diet (LED) is an effective approach to induce a rapid weight loss in individuals with overweight. However, reported disproportionally large losses of fat-free mass (FFM) after an LED trigger the question of adequate protein content. Additionally, not all individuals have the same degree of weight loss success. After an 8-week LED providing 5020 kJ/d for men and 4184 kJ/d for women (84/70 g protein/d) among overweight and obese adults, we aimed to investigate the relationship between protein intake relative to initial FFM and proportion of weight lost as FFM as well as the individual characteristics associated with weight loss success. We assessed all outcomes baseline and after the LED. A total of 286 participants (sixty-four men and 222 women) initiated the LED of which 82 % completed and 70 % achieved a substantial weight loss (defined as >= 8 %). Protein intake in the range 1 center dot 0-1 center dot 6 g protein/d per kg FFM at baseline for men and 1 center dot 1-2 center dot 2 g protein/d per kg FFM at baseline for women was not associated with loss of FFM (P = 0 center dot 632). Higher Three-Factor Eating Questionnaire (TFEQ) hunger at baseline and reductions in TFEQ disinhibition and hunger during the LED were associated with larger weight loss (all P <= 0 center dot 020); whereas lower sleep quality at baseline predicted less successful weight loss using intention to treat analysis (P = 0 center dot 021), possibly driven by those dropping out (n 81, P = 0 center dot 067 v. completers: n 198, P = 0 center dot 659). Thus, the protein intakes relative to initial FFM were sufficient for maintenance of FFM and specific eating behaviour characteristics were associated with weight loss success.